Controlling bacterial infections is of immense importance with applications ranging from health care setting to improving the quality of day to day life.1 The increase of bacterial resistance to available antibiotics emphasizes the need for robust and versatile antimicrobials in controlling pathogenic bacteria. Different strategies have been developed towards new antimicrobial agents and polymers have taken the central stage as they have the advantage of being fabricated on to variety of formats.2-5 We and others have explored and established the biocidal properties of cationic conjugated polyelectrolytes (CPEs).2,6-8 Recently, we synthesized a series of cationic phenylene ethynylene oligomers (OPEs) with different lengths (repeat unit=1, 2, and 3) and examined structure-reactivity relationships between their photophysical photophysical properties and antibacterial activity.9-12 These studies show that OPEs possess profound light activated biocidal activity. Photophysical studies reveal the OPEs are efficient sensitizers for singlet oxygen which is believed to play an important role in the light induced biocidal activity. The absorption of the OPEs is limited to the near-UV region, extending towards the violet region of the visible spectrum as the number of repeat unit increases to 3.